Instructions for replacing pinion gear in T-Rex Rotary extractors (Does not apply to T-Rex Jr.). For models with a chrome gearbox, use H129 pinion gear, for models with powder black gearbox, use H914 pinion gear.
Tools Needed:
- Philips screwdriver
- Rubber mallet
- 1 1/4" wrench
Step 1: Remove the four bolts holding the transmission 
and motor together.
Step 2: Pull the motor off the transmission. You can
use a rubber mallet to loosen the seal if necessary
(Figure A).
Step 3: Use a Phillips head screwdriver to unscrew the
6 screws on the transmission cap (Figure B). Remove
the transmission cap.
Step 4: Remove the broken pinion gear.
Step 5: Install the new pinion gear by inserting
the gear side into the space beside the large
transmission gear. Use the existing grease inside the
transmission to lube the pinion gear (Figure C). Twist
the pinion gear to make sure the gears are aligned.
You should see the large gear spin a little (Figure D).
Step 6: Make sure the wave washer is centered on
the bearing for the large gear (Figure E). Line up the
pins on the transmission casing with the holes on the
transmission cap and tap the cap into place (Figure
F). The transmission should be on a surface that
allows the threaded shaft on the bottom to hang free
so that it doesn’t push back up against the cap as
you’re trying to tap the cap back on (Figure G).
Step 7: Replace the screws with a Phillips screwdriver.
The longer screw goes in the hole in the motor cavity.
Step 8: Twist the pinion gear by hand to make sure it is aligned properly.
You will see the bearing for the main gear spin slightly.
Step 9: Match the locking key on the motor shaft to the key slot on the transmission and slide the motor back in place (Figure H). Line up the bolt holes and make sure the power cord is coming out the back.